Thus, infection and vaccination were associated with phenotypically distinct memory B cell populations with a higher proportion of CXCR3+CD21+ BSM including CXCR3+IgA+ cells post-infection, and BSM populations with lower CD21 expression and lacking CXCR3 post-vaccination in the tissues, analogous to the peripheral blood. The gene discussed is CXCR3; the disease is infection.